Hello folks,
I'm having a peculiar problem after cleaning my choke plate and linkage this morning. My 86' is really hard to start and has a really rough idle. If I try to move it, it has no power at all and dies after ten feet or so.
My initial problem was that my idle speed was way too high - 1500+ rpm. I tried adjusting the idle speed screw with no effect. So I read on these forums to make sure the choke was working correctly (closed at start, open up as it warms). As I was taking off the vac lines I noticed that my Line A (according to Fastboatman's awesome post) was not attached to the same port on the air cleaner assembly as in his post, but I decided that it was fine since the truck was running fine before this morning, just a fast idle. So I cleaned the carb and choke and put all the vac lines on the air cleaner, tried to adjust the idle and it worked, it idled around 900-1000. However, I noticed an audible vac leak, which seemed to be coming from the choke plate itself.
I'm pretty sure my problem is with the audible vac leak, I'll wait until the engine has cooled down some, then check if I can put all the vac lines according to Fastboatman's post.
If anyone has any ideas, I would greatly appreciate it.
Rough Idle After Cleaning Carb, Choke, Linkage
Re: Rough Idle After Cleaning Carb, Choke, Linkage
I worked on the truck this morning, and I corrected the inaccuracies in the vac lines.
I've got it to idle, but the loud hissing sound still persists.
Before I crank the engine, the choke plate is fully closed, then when the engine turns over, the plate opens up a bit and the hissing sound starts.
I was about to adjust the choke mechanism (the little black circle towards the rear of the carb), only to find that the 3 screws mentioned in other posts were not on my choke mechanism, rather there were two silver pins.
Does anyone have any idea how to get these off and where the third pin would be (if there is one)?
Also, apparently the previous owner put a green bind on the choke linkage (?), would it be okay to take this off?
I'll post some pictures as soon as I figure out how to.
I've got it to idle, but the loud hissing sound still persists.
Before I crank the engine, the choke plate is fully closed, then when the engine turns over, the plate opens up a bit and the hissing sound starts.
I was about to adjust the choke mechanism (the little black circle towards the rear of the carb), only to find that the 3 screws mentioned in other posts were not on my choke mechanism, rather there were two silver pins.
Does anyone have any idea how to get these off and where the third pin would be (if there is one)?
Also, apparently the previous owner put a green bind on the choke linkage (?), would it be okay to take this off?
I'll post some pictures as soon as I figure out how to.
Re: Rough Idle After Cleaning Carb, Choke, Linkage
Here's a link to one pic that shows the other two
http://s1248.photobucket.com/user/lmari ... 8.jpg.html
http://s1248.photobucket.com/user/lmari ... 8.jpg.html
Re: Rough Idle After Cleaning Carb, Choke, Linkage
Don't touch the choke heater (that black, round thing that is riveted closed). That is designed to open at a steady rate depending on the temperature, and any issues you're having with the vehicle will not be caused by that, unless it's already been tampered with.
That said, it's somewhat concerning that the green zip tie is on there. Perhaps something was broken?
Also, lines A and B cannot be reversed. That is a vacuum leak. Your vacuum hoses should match fastboatman's description as closely as possible. The mechanism that lines A and B connect to is a temperature-controlled vacuum valve. The "A" side should be under constant manifold vacuum. The "B" side will either be connected to vacuum or open to ambient pressure, depending on the temperature. B controls a vacuum motor in the intake that controls whether the incoming air originates from the warm area near the exhaust (via the metal riser hose), or from the cooler area behind the headlights.
In general there's a lot of stuff driven by vacuum valves in this system. Each valve will have an "upstream" port (source of vacuum), and a one or more downstream ports (components that need vacuum). You wouldn't hook up an ignition coil backwards, right? This is the same deal.
That said, it's somewhat concerning that the green zip tie is on there. Perhaps something was broken?
Also, lines A and B cannot be reversed. That is a vacuum leak. Your vacuum hoses should match fastboatman's description as closely as possible. The mechanism that lines A and B connect to is a temperature-controlled vacuum valve. The "A" side should be under constant manifold vacuum. The "B" side will either be connected to vacuum or open to ambient pressure, depending on the temperature. B controls a vacuum motor in the intake that controls whether the incoming air originates from the warm area near the exhaust (via the metal riser hose), or from the cooler area behind the headlights.
In general there's a lot of stuff driven by vacuum valves in this system. Each valve will have an "upstream" port (source of vacuum), and a one or more downstream ports (components that need vacuum). You wouldn't hook up an ignition coil backwards, right? This is the same deal.
Re: Rough Idle After Cleaning Carb, Choke, Linkage
Thanks for the knowledge.
I had an idea that perhaps my fast idle cam is not functioning correctly (I tried checking it this morning, but there are too many things in the way to get a good look at the steps) because if my choke lever does not open up all the way, completely vertical, then the fast idle cam cannot disengage, correct?
The green zip tie looks to be blocking the butterfly valve from opening up all the way. Does anyone have a picture of what that lever/spring is supposed to look like?
That being said, I wanted to cut the zip tie, unless it would undo something that is broken for some reason.
So the situation now is that my idle is higher than ever approx. 1800 rpm, and while the engine is warming up it idles fine around 1300 as it should while the fast idle cam is engaged, then if I push the throttle at all it shoots up to 1500+. Then during normal driving the idle remains constantly hovering just below 2000 rpm.
Also, the loud hissing sound remains, still seems to be coming from the carb itself.
I had an idea that perhaps my fast idle cam is not functioning correctly (I tried checking it this morning, but there are too many things in the way to get a good look at the steps) because if my choke lever does not open up all the way, completely vertical, then the fast idle cam cannot disengage, correct?
The green zip tie looks to be blocking the butterfly valve from opening up all the way. Does anyone have a picture of what that lever/spring is supposed to look like?
That being said, I wanted to cut the zip tie, unless it would undo something that is broken for some reason.
So the situation now is that my idle is higher than ever approx. 1800 rpm, and while the engine is warming up it idles fine around 1300 as it should while the fast idle cam is engaged, then if I push the throttle at all it shoots up to 1500+. Then during normal driving the idle remains constantly hovering just below 2000 rpm.
Also, the loud hissing sound remains, still seems to be coming from the carb itself.